From his home office on a Los Gatos cul-de-sac, Mark Coker is part of a digital movement ruffling the pages of the publishing industry, helping to speed readers’ transition from words in print to words on a screen.

The founder of Smashwords, an electronic book publishing platform for self-published authors and small publishers, Coker thinks the transition from print to electronic books, for many readers, is inevitable.

Less clear, he says, is where readers will store the e-books they buy. Will those virtual libraries live on a personal device, such as Amazon’s Kindle? Or will people choose to store their e-books on the Internet “cloud,” on networks accessible through any computer or smart-phone? And how portable will readers’ digital libraries be? Will readers be able to share their e-books the way you pass a treasured paper book on to a good friend?

The publishing world is going through rapid change, which is clear this holiday season as large numbers of consumers embrace electronic books available for download to devices such as the Kindle, Barnes & Noble’s Nook and Sony’s Reader.

The change has been so tumultuous that several New York publishing houses have decided to delay releasing books in their electronic format for months, concerned that the availability of $9.99 e-books will slice into the sales of traditional hardcover editions that may sell for three times that price.

Already, many readers are using public libraries as a kind of e-book “cloud.” The library e-book distributor OverDrive predicts downloads of e-books and other library content will hit 19 million in 2009 — roughly the volume for the years 2003-08 combined.

Starting in 2010, however, anybody who wants to read an e-book will have to choose more than just which reader they buy. Increasingly, consumers will have an array of e-book access choices, such as buying perpetual access to a book stored on the Internet, downloading a book to a personal device or perhaps some other model. New reader devices are also due to hit the market from Mountain View-based Plastic Logic, Fremont-based Spring Design, and perhaps Apple, which is widely expected to release a tablet reader in 2010.

Music consumers used to buying and downloading digital music files to a device such as Apple’s iPod or Microsoft’s Zune may soon have new storage choices as well.

Two of Silicon Valley’s most influential companies may be moving digital books and music to the cloud, freeing readers and listeners from having to use a particular device to enjoy content they have purchased.

By next holiday season, Google plans to offer an online retail service for e-books that will allow readers to buy access, in perpetuity, to any e-book stored on Google’s network.

“Our vision is basically to provide a great consumer model for buying digital books, using the browser in a sort of device-agnostic way,” said Google spokesman Gabriel Stricker. “It could be on a Web-enabled laptop, a desktop or a phone, a tablet — any of those things. Our vision of it is to provide an open platform for reading and accessing books.”

The retail service, to be called Google Editions, will be only for newly published books and is separate from the Internet giant’s highly controversial plan to scan existing out-of-print books, splitting the proceeds with any rights-holders it can locate. Google won’t say how much a newly published e-book will cost on Editions, but it has tried to steer speculation away from talk of the service being an “Amazon-killer” that uses Google’s dominant search engine to siphon book-buying traffic from the e-retailer.

Meanwhile, Apple’s recent purchase of Palo Alto-based Lala.com, an online music streaming service, has triggered speculation that Apple is positioning its iTunes platform to begin a move to the cloud. (A spokesman declined to comment about Apple’s plans for Lala.)

Consumers may feel different about keeping their music on the cloud than keeping their books on the cloud, said Tim Westergren, founder of Pandora, the Internet music streaming service.

For music, “I think it’s going to be a long time before ownership goes to the cloud,” Westergren said. He believes music owners will be more leery than book owners about permanently storing their digital libraries on an outside network beyond their control, because people revisit songs in their digital libraries more times than they revisit books they have already read.

There are pros and cons to storing a book or a song online rather than on a device. If you lose your iPod or Kindle, the content is gone, too, although Amazon allows readers to access their entire library of previously purchased Kindle books at no charge if something happens to the device. There would be no limit to how many books or songs could be stored on the cloud.

On the other hand, if you are on a trek in the Yosemite high country and suddenly decide you want to reread the copy of “Freakonomics” you bought last month from Google Editions, you’ll be out of luck, because you can’t access the cloud without an Internet connection. That said, you could have cached the book on your smartphone before you set off into the woods.

A bigger issue for e-book readers may be the different proprietary formats that govern the Kindle, the Reader and the Nook. That would prevent a reader who wants to switch, say, from using Amazon’s Kindle to Sony’s Reader from transporting her e-books to the other device.

The Kindle’s format also does not support downloads of e-books in the format used by many public libraries, although Amazon counters that thousands of public-domain books are available in the Kindle store, including many free classics. Customers can use sites such as Gutenberg.org, Google and Internet Archive to access other e-books.

Coker predicts that consumers won’t be pleased when they realize the differing formats and copy-protection code called Digital Rights Management (DRM) is like a fence around their e-book collections, one that publishers say is necessary to protect them from e-book piracy.

“Over the long haul,” Coker predicts, “customers are not going to want to have their library in the cloud fractured across 20 different retailers.”

Smashwords does not wrap its text with DRM coding, and it allows readers to use both a device model or a cloud model to access their e-books. With more than 5,000 e-books for sale at smashwords.com, the company has deals that allows readers to download to the Kindle, the Reader or the Nook. But the company also allows customers to buy permanent access to any e-book stored on Smashwords’ network, allowing them to read it at any time from any smartphone or computer with a Web browser.